A Comparison of the Recursive and FFT-based Reassignment Methods in micro-Doppler Analysis

International audienceA brief comparison of two time-frequency (TF) reassignment methods is provided in this paper. Both techniques use the short-time Fourier transform (STFT), however, they can be formulated and computed differently. The first classical method is based on the fast Fourier transform (FFT), while the second one uses a recursive filter bank which, in turn, can be more efficient due to a lower time delay and a reduced computational complexity. Thanks to the proposed methodology, a real-time computation of the spectrogram and the reassigned spectrogram can be obtained. Hence, the reassignment method allows an almost ideal localization of the micro-Doppler signature components in a TF distribution to be obtained. Both approaches are presented, investigated, and validated using real-life radar signals in the form of micro-Doppler signatures originating from different targets